New software instantly connects key bits of data that once eluded teams of researchers

Quick: What do Hamas terrorists have in common with Martha Stewart? No, we're not talking about their public-approval ratings. Rather, both may have drawn unwanted scrutiny in part because of the same piece of software.

The data-mining algorithms of ClearForest, based in New York City, are at work within both Israeli security agencies and NASDAQ. Israel uses them to drill for hidden connections among suspected terrorists: say, a pattern of phone calls shortly before each of several suicide bombings. NASDAQ uses the same software to detect block trades of stock quietly placed just before the release of company news--including sales...